Drawbar mechanism for electric chucking machines



Dec. 28, 1937. A, E, DR NER 2,103,350

DRAWBAR MECHANISM FOR ELECTRIC CHUCKING MACHINES Filed Oct. 9, 1956INVElVTOR STATS PATENT DRAWBAR MECHANISM FOR ELECTRIC CHUCKING MACHINESAlfred E. Drissner, Cleveland, Ohio, assignor to The National AcmeCompany, Cleveland, Ohio, a corporation of Ohio Application October 9,1936, Serial No. 104,771

28 Claims. (01. 2938) This invention relates to electrical chucking toolwill take a heavier cut on one side than on mechanisms for automaticmultiple spindle maanother or perhaps have a jumping action due chinesof that type known as automatic chuckto the uneven surface, thuspermitting the diaing machines having a sliding tool carrier and mondserrations to dig deeper into the material,

an indexible work spindle carrier provided with thereby loosening thepressure between the jaw 5 a plurality of rotatable work spindles havingand the piece chucked so that it is found dechucks for the reception ofrough forgings or sirable to have a follow-up pressure. For thiscastings to be operated upon by the tools carried purpose, I haveprovided a spring designed for by the tool slide, the object of theinvention the pressure required on different classes of being to providean improved cushioning or Work. l0 follow-up means for effecting a moreefficient In electrical chucking machines, the preslocking of the chuckson the work piece. sure is a fixed'unit and where the chucks, dur- Afurther object of the invention is the proing the cutting operation tendto loosen, there vision in an electrically operated chucking mechisnothing to follow up the pressure on the chucks 35 anism of a follow-upcushioning means located and it is, therefore, one of the primary ob- 15between a bearing thereof and the work spindle, jects of the presentimprovement to provide a and which is simple in construction andefficient simple, efficient and inexpensive means to follow inoperation. up the chucks and maintain a constant pres- The presentinvention is an improvement upon sure.

g0 and is intended for use in connection withelec- In the drawingaccompanying and forming a trical chucking mechanisms such as shown andpart of this specification, Fig. 1 is a longitudinal described in thecontemporaneously pending apsectional view of the left hand end of oneof plications of C. W. Simpson, Serial Numbers the chuck spindlesillustrating the means for 50,538 and 101,651, filed November 19th,1935, controlling the operation of the draw bar with 5 and September16th, 1936, respectively, and asthis improved spring or cushion means inposlsigned to The National Acme Company, of Clevetion.

land, Ohio, the assignee of the'present improve- Fig.2 is a face view ofone form of cushioning ment and may be used with other chucking mameans,chines of the same general character. There- Fig. 3 is an edge viewthereof, and

3-1 fore, it is deemed necessary to illustrate herein Fig. 4 is alongitudinal sectional View of the only so much of these applications asis essenright hand of one of the chuck spindles illustrattial todisclose the present improvement. ing the manner of operating the chuckby the In these electrical chucking machines, it is draw bar.

desirable, for different classes of work, to pro- Similar characters ofreference indicate cor- :13 vide a cushion for high pressure between theresponding parts in the several views. draw rod controlling the chucksand adapters and Before explaining in detail the present imthe rotatingsleeve or nut controlling the draw movement and mode of operationthereof, I derod. In other words, when the electrical motor sire to haveit understood that the invention operates the rotating sleeve or nut ofthe draw is not limited to the details of construction and 4c rod,pressure is built up against the ball thrust arrangement of partsillustrated in the accombearing of the sleeve and the adapter fastenedpanying drawing since the invention is capable to; the end of the rotaryspindle and when this of other embodiments, and that the phraseologysleeve or nut has tightened, there is a fixed presemployed is for thepurpose of description and sure between the draw rod and the sleeve ornot of limitation. 4-5 thrust bearing. Reference is made to theapplications herein- If the forging or casting to be chucked shouldbefore referred to for a description of the elechave thin walls and thediamond of the serration trical operating mechanism, it being suificientto of the chuck jaws penetrate the material, they say in the presentinstance that the sliding shaft being held in a fixed position and withpositive 30 provided with lugs or projections ill, is auto-' pressurecontrolled by the draw rod, there are matically shifted back and forthto engage and 50 times when these diamond serrations will dig rotate thedraw bar operating sleeve i9 having deeper into the material during themachining similar lugs 4i and, in the earlier application, operations onthe work held by the chucks, and this shaft is electrically rotated,while, in the in these machining operations, especially on f0rg-. laterapplication it is electrically reciprocated ings and castings which arenot uniform, the and rotated to perform its proper operations. 5

The indexible spindle carrier is provided with a plurality of rotatablechuck carrying spindles [2, only one of which is illustrated. Each ofthe rotatable spindles 12 has on its rear end a clutch l3 (see Fig. 1)of the common twin disk type for driving and stopping the spindle, thisclutch being operated automatically by a sliding spool M at the propertime and shiftable by a yoke from suitable mechanism. The disk clutch Acontrols the rotation of the spindle and the disk clutch B acts as abrake to hold the spindle in a fixed position.

On the inside of the spindle is a draw rod l5 suitably connected at itsforward end with the chuck jaws to open and close the sameand it may beconnected with a two, three or four jaw chuck, an adaptor, or anysuitable means necessary to hold the different types of work such ascastings or forgings during the turning and boring operations. For thispurpose, the forward end of the draw bar (see Fig. 4) has a threadedportion 46 for engaging a threaded member connected to levers 4? forshifting the chuck jaws as hereinafter described.

This draw rod or bar is keyed or splined within the spindle to preventits turning, as at it, and is also provided with a thread 57 and has atits end an annular recess l8 for the reception of a guide collar.

Between the draw rod and spindle is located a bronze flanged orshouldered nut or sleeve l9 having the lugs 4| on the end thereof andwhich turns freely inside the spindle l2. Tln's nut or sleeve isprovided with ball thrust bearings 20 and 43 to take up the thrust, thenut is turning freely when driven by the sliding shaft 3i) connectedwith an electric motor (not shown).

Screwed on the end of the spindle and fastened thereto is a shoulderednut 22 controlling the adjustment and alignment of the clutches l3. Thisnut 22, together with the shouldered nut 23, threaded on the nut 22 andsecurely held thereto by a key 24, holds the rotating nut or sleeve l9endwise within the spindle with suihcient clearance for the nut to turnfreely and permit the insertion of the cushioning means 44 in the formof an annular spring having high and low spots. In other words, thespring is formed with spaced projections or bulges.

Suitable means, of course, is provided for rotating the chuck spindlesl2 and is illustrated in the applications referred to. The rotation ofthe nut or sleeve i9 is obtained by means of the rotating and slidingshaft 30 hereinbefore referred to which shaft is rotated and shifted inthe manner set forth in said applications,

Thus, when the cushioning spring is inserted between the nut 22 and thethrust bearing 29, as shown in Fig. 1, it will be seen that when the nutI9 is rotated, the draw bar I5 will be shifted toward the rear of themachine or to the left, as shown in the drawing, by the operation of thethreaded portion of the nut l9 upon the thread ll of the draw bar l5. Asthe draw bar I5 moves to the left, the pressure on the nut 19, being thereverse or in the opposite direction, the cushion spring 44 iscompressed in a load normally approximately 5,000 pounds tending toflatten out the high spots of the spring whereupon a slight space isformed adjacent to the bearing 43. The spring 44 thus becomes effectiveupon the withdrawalof the shaft 39 with its lugs 53 to urge the draw barfurther to the left, thereby following up the chucks wherethey dig intothe work during the machining operation.

In other words, when the shaft driven by the electrical motor engagesthe sleeve or nut l9, pressure is built up against the ball thrust 20and the shoulder on the nut 22. Consequently, when the nut H! hastightened, there is a fixed pressure between the draw rod and the nut orsleeve i9 and the thrust bearing so that, as before stated, when thechuck is closed by the draw rod, the spring 44 is compressed and whenthe jaws have a tendency to grip the piece more tightly or dig deeperinto the forgings or castings, this spring will expand and follow up thepressure and hold the piece firmly until the machining operation iscompleted.

' When it is necessary to release the chucks from the work, the shaft 30is again'shifted into position for the lugs 40 to engage the lugs 4! ofthe nut i9 and it is turned in the opposite direction, thus releasingthe pressure on the spring and causing the member M9 to shift to theleft and the draw rod to shift to the right. As the draw rod moves ineither direction, the levers 4". pivoted at 48 move the chuck jaws in orout to chuck or unchuck the work.

Thus, in the operation of this mechanism, when the nut or sleeve 19 isrotated by the shaft 30, it shifts the draw bar H to the rear, therebyclosing the chuck jaws on to the work and, of

course, tightening them thereon.

During this movement of the draw bar, the sleeve, of course, is shiftedslightly in the opposite direction or toward the front end of thespindle,

the movement of the sleeve being sui'hcient to compress the high spotsin the spring so that when the shaft 30 is withdrawn from the sleeve,the expansion of this spring will cause the sleeve to hold the draw barin the desired position and maintain the chuck jaws tight on the work.

This spring thus acts as a follow-up means and a cushioning means forthe parts so that when the draw bar has been shifted by the shaft 30 asfar as possible to tighten the chucks, the expansion of the springcontinues to exert a tension on this draw bar and hold it in positionand take up any movement of the serrated jaws of the chucks in the eventthey dig in deeper or if, for any reason, there is any tendency of thework to become loose from the jaws.

' It will be understood, of course, that the springs 44 are designed fordifferent pressures to take care of various classes of work anddifferent wall thicknesses of work. For instance, if it takes 5,000pounds pressure to hold the piece in the chuck, the electric means isregulated for that pressure in the manner set forth in the earlierapplication hereinbefore referred to so that when the jaws grip thework, this pressure will compress the spring in the manner hereinbeforedescribed thereby enabling the spring to follow-up this pressure on thework.

.It is to be understood that, by describing in detail herein anyparticular form, structure or arrangement, it is not intended to limitthe invention beyond the terms of the several claims or the requirementsof the prior art.

Having thus explained the nature of my said invention and described away ofconstructing and using the same, although without attempting toset forth all of the forms in which it may be made or all of the modesof its use, I claim: l. A chucking mechanism comprising a draw baroperated chuck and rotatable operating means therefor, and means forurging the entire draw bar in its chuck locking direction after therotatable operating means has performed its work of closing the chuck.

2. A chucking mechanism comprising a draw bar operated chuck andoperating means therefor, and resilient means for pushing the draw barin its chuck locking direction after the operating means has performedits work of closing the chuck.

3. A chucking mechanism. comprising a draw bar operated chuck andoperating means therefor, and means comprising an annular spring forurging the entire draw bar in its chuck locking direction after theoperating means has formed its work of closing the chuck.

i. A chucking mechanism comprising a draw bar operated chuck androtatable operating means therefor, and means comprising a compressibleannular spring having high and low spots and operative on its expansionfor urging the draw bar in. its chuck locking direction upon the releaseof, its rotatable operating means.

5. A chucking mechanism for multiple spindle machines comprising achuck, a draw bar shiftable in opposite directions for ope-rating thechuck, a rotatable threaded sleeve for shifting the draw bar, means forrotating said sleeve, means for limiting the endwise movement of saidsleeve, and means co-operating with the sleeve and endwise limitingmeans for urging the sleeve and draw bar in its chuck locking directionupon release of the rotating sleeve.

6. A chucking mechanism comprising a draw bar operated chuck andinternally threaded rotatable means for sliding the draw bar, means forlimiting the endwise movement of said rotatable means, and spring meansfor urging the draw bar into its chuck locking position after thecessation of rotation of said rotating means.

7. A chucking mechanism comprising a draw bar operated chuck andinternally threaded means for sliding the draw bar upon its rotation andhaving a shoulder, shouldered nuts for limiting.

endwise movement of said threaded means, and

a spring cushion between a pair of said shoulders.

for urging the draw bar in its chuck locking direction upon thecessation of rotation of said internally threaded means.

8. A chucking mechanism comprising a draw bar operated chuck androtatable internally threaded means for sliding the draw bar upon itsrotation, a thrust bearing for said threaded means, means for limitingendwise movement of said threaded means, and means cooperating with saidthrust bearing and limiting means for urging the draw bar in its chucklocking direction upon the cessation of rotation of said internallythreaded means.

9. A chucking mechanism comprising a draw bar operated chuck,electrically operated means therefor and means for pushing the draw barin its chuck locking direction after the operating means has performedits work of closing the chuck.

10. A chucking mechanism comprising a draw bar operated chuck andelectrically operated means therefor including a bearing supportedrotatable means, and means co-operating with said bearing for urging thedraw bar in its chuck looking direction after the operating means hasperformed its work of closing the chuck.

11. A chucking mechanism comprising a draw bar operated chuck andoperating means therefor including a bearing supported meana'and meansco-operating with said bearing for urging the draw bar in its chucklocking direction after the ing the chuck.

12. A chucking mechanism comprising a draw bar operated chuck andoperating means therefor, and mechanical means for pushing the entiredraw bar in its chuck locking direction after the operating means hasperformed its work of closing the chuck.

13. In a chucking machine having a spindle carrier provided witha rotarychuck carrying spindle, a unit within each spindle for operating itschuck and comprising a shiftable draw rod, an electrically operatedthreaded driving sleeve for shifting said rod, a thrust bearingco-o-perating with said sleeve, and a draw rod follow-up cushioningmeans for said hearing effective to control equal pressure on the workat certain times.

14. In an electric chucking mechanism having a motor driven shaft, arotary chuck carrying spindle, a draw rod therein for controlling thechuck, a driving sleeve operated by the motor driven shaft and providedwith an internal thread controlling the back and forth movement of thedraw rod, a thrust bearing for the sleeve, and a draw rod follow-upmeans co-operating with said thrust bearing. I

15. In an electric chucking mechanism having a motor driven shaft, arotary chuck carrying spindle, a draw rod therein for controlling thechuck, a driving sleeveoperated by the motor driven shaft and providedwith an internal thread controlling the back and forth movement of thedraw rod, a thrust bearing for the sleeve, and a draw rod follow-upmeans co-operating with said thrust bearing and comprising a spring.

16. In an electric chucking mechanism having a motor driven shaft, arotary chuck carrying spindle, a draw rod therein for controlling thechuck, a driving sleeve operated by the motor driven shaft and providedwith an internal thread controlling the back and forth movement of thedraw rod, a thrust bearing for the sleeve, and a draw rod follow-upmeans co-operating with said thrustv bearing and comprising a springlocated between the thrust bearing and the spindle.

17. In a chucking machine having a spindle carrier provided with arotary chuck carrying spindle, a unit within each spindle for operatingits chuck and comprising a shiftable draw rod, an electrically operatedthreaded driving sleeve for shifting said rod, a thrust bearingco-operating with said sleeve, and a draw rod follow-up cushioning meansfor said bearing effective to control equal pressure on the work atcertain times and located between the thrust bearing and the spindle.

18. A chucking mechanism for multiple spindle machines comprising achuck, a threaded draw bar shiftable in opposite directions foroperating the chuck, an electrically operated shouldered and threadedrotatable sleeve for shifting the draw bar, means for limiting endwisemovement of said sleeve and comprising a pair of shouldered nuts, athrust bearing for said sleeve, and spring means between said bearingand a shoulder of one of said parts for urging the sleeve and its drawbar in its chuck locking direction upon the release thereof from theelectrical operating means.

19. A chucking mechanism for multiple spindle machines comprising achuck, a threaded draw bar shiftable in opposite directions foroperating the chuck, an electrically operated shouloperating means hasperformed its work of closdered and threaded rotatable sleeve forshifting the draw bar, means for limiting endwise movement of saidsleeve and comprising a pair of shouldered nuts, a thrust bearing forsaid sleeve and located between a shoulder of said sleeve and theshoulder of one of said nuts, and spring means between said bearing andsaid nut for urging the sleeve and its draw bar in its chuck lockingdirection upon the release thereof from the electrical operating means.

20. A chucking mechanism comprising a draw bar operated chuck androtatable operating means therefor, and means located laterally of theperiphery of said rotatable operating means for pushing the draw bar inits chuck locking direction after the rotatable operating means hasperformed its work of closing the chuck.

21. A chucking mechanism comprising a draw bar operated chuck androtatable operating means therefor, and means co-operating with saidrotatable means for urging the draw bar in its chuck locking directionupon the cessation of rotation of said rotatable operating means.

22. A chucking mechanism comprising a draw bar operated chuck andoperating means for operating said draw bar, and means co-operating withsaid draw bar operating means for urging the draw bar in its chucklocking direction upon the release of its operating means.

23. A chucking mechanism comprising a draw bar operated chuck andoperating means therefor, and compressible means operative on itsexpansion for urging the draw bar in its chuck locking direction afterthe chuck operating means has performed its work of closing the chuck.

24. A chucking mechanism comprising a draw bar operated chuck androtatable operating means therefor, and compressible means operative onits expansion for urging the draw bar in its chuck locking directionafter the chuck operating means has performed its work of closing thechuck.

25. A chucking mechanism comprising a draw bar operated chuck andoperating means therefor, the same operating means efiective to shiftthe draw bar in opposite directions, and means supported independentlyof the draw bar for urging the draw bar in its chuck locking directionupon the release of its chuck operating means.

26. A chucking mechanism comprising a draw bar operated chuck androtatable operating means therefor, and means supported independently ofthe draw bar for urging the draw bar in its chuck locking direction uponthe release of its chuck operating means.

27. A chucking mechanism comprising a draw bar operated chuck, said drawbar having a threaded portion and a portion in front thereof operativelyconnected with the jaws of the chuck, rotatable operating meanstherefor, and means cooperating with the threaded portion of the drawbar for pushing said draw bar into its chuck locking direction upon thecessation of rotation of said rotatable operating means.

28. A chucking mechanism for multiple spindle machines comprising achuck, a draw bar shiftable in opposite directions for operating thechuck, a'rotatable threaded sleeve for shifting the draw bar, meansforrotating said sleeve, and

means cooperating with the sleeve for urging the sleeve and draw bar inits chuck locking direction upon the cessation of rotation of said r0-tating sleeve.

ALFRED E. DRISSNER.

